General distributed file systems (DFSs) or technologies mainly use a plurality of nodes connected with storing apparatuses and a file accessing server connected with the nodes simultaneously to access data of the storing apparatuses. After a file is retrieved, most of the file accessing servers firstly determine a storing apparatus having a low utilization factor and directly store the file into this storing apparatus. On the other hand, the retrieved file is usually stored in a fixed number of backups to ensure that, in case a part of the storing apparatuses is corrupted to cause loss of the original file content, the accessing operation can still be accomplished successfully by use of the backups of the file.
However, in order to facilitate maintenance of the system and to maintain the convenience in operation of the system in the conventional DFS architecture, the storing apparatuses connected with the nodes usually need to have the same hardware property and the same accessing speed level. This often makes it impossible to make a compromise between the accessing speed and the hardware cost and leads to a significant decrease in the flexibility in use of the system.
Further, in the conventional DFSs, the number of backups of the file is determined by the system operator early when the system is initiated, so the number of backups cannot be adjusted during the operation depending on the importance level of or the number of accesses to the file. This also leads to a low flexibility in use of the system.
Accordingly, an urgent need exists in the art to overcome the shortcomings of the prior art so as to improve the flexibility in use and the reliability of the system.